Integrated Air-Sea Interfacial Layer Turbulence Observation from Drifting Platforms

To advance the understanding of air-sea interfacial layer turbulence that governs the air-sea energy exchange, we employed a new integrated observing strategy using two small drifting platforms. The first NRL drifting platform is a unique buoy called “Ocean Air Research Buoy for Interfacial Turbulence & Environmental Reporting (OARBITER)” and the 2^nd drifting platform is called “Turbulence Ocean Surface (TurbOSurf)”. OARBITER has atmospheric and ocean turbulence sensors as well a small spotter wave buoy tethered to the main buoy to record the ocean surface waves. TurbOSurf carries a suite of ocean turbulence sensors to measure the upper 5 m of ocean turbulence structure. Field testing of both drifting platforms was conducted during spring of 2024 over Gulf Mexico. Both platforms were deployed into the ocean and drift about < 1 m/s along a cyclonic oceanic eddy trajectory for few hours. The test period was characterized by post-frontal conditions, high pressure, low to moderate surface wind, current, and about 1 m significant wave height. These two platforms captured the weakening of the ocean diurnal warm layer resulting in surface cooling of several tenths of a degree Celsius, as well as the diurnal transition in direction of the sensible heat flux between the atmosphere and ocean. The air-sea temperature difference is about 1 °C. Spectral analysis of 2 m temperature, humidity, pressure, and wind show departure from the Komogorov theory.